Optimization of stripline-based microfluidic chips for high-resolution NMR.

We here report on the optimization, fabrication and experimental characterization of a stripline-based microfluidic NMR probe, realized in a silicon substrate. The stripline geometry was modelled in respect of rf-homogeneity, sensitivity and spectral resolution. Using these models, optimal dimensional ratios were found, which hold for every sample size. Based on the optimized parameters, a simple integrated stripline-based microfluidic chip was realized. The fabrication of this chip is described in detail. We achieved a sensitivity of 0.47 nmol/square root(Hz) and a resolution of 0.7 Hz. The rf-homogeneity (A(810 degrees)/A(90 degrees)) was 76% and was proved to be suitable for 2D-NMR analysis of glucose.